Phase 1 study of MK-4166, an anti-human glucocorticoid-induced tumor necrosis factor receptor (GITR) antibody, as monotherapy or with pembrolizumab (pembro) in patients (pts) with advanced solid tumors.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 9509-9509 ◽  
Author(s):  
Kyriakos P. Papadopoulos ◽  
Karen A. Autio ◽  
Talia Golan ◽  
Konstantin Dobrenkov ◽  
Elliot Chartash ◽  
...  

9509 Background: Ligation of GITR on immune cells decreases Treg-mediated suppression and enhances T cell proliferation. MK-4166 is a humanized IgG1 agonist monoclonal antibody targeting GITR. Data from the first-in-human phase 1 study (NCT02132754) of MK-4166 as monotherapy (mono) or in combination with pembro (combo) are presented. Methods: MK-4166 was tested alone (0.0015 mg IV-900 mg Q3W ×4 doses) or with pembro (fixed dose 200 mg IV Q3W up to 35 doses) in the absence of toxicity or progression. Study included a dose escalation/confirmation cohort (metastatic solid tumors) and an expansion cohort (treatment-naive and pretreated melanoma). A T cell–inflamed gene expression profile (GEP) was assessed using RNA from baseline tumor samples. End points – primary: safety/tolerability, maximum tolerated dose (MTD) of MK-4166; secondary: pharmacokinetics (PK), pharmacodynamics (PD); exploratory: objective response rate (ORR) per irRECIST1.1. Results: Of 113 pts, 48 received mono and 65 combo; 20 were in the melanoma expansion. Common AEs ( > 20%) were fatigue, infusion-related reaction, nausea, abdominal pain, and pruritus; 43 pts had grade ≥3 AEs (38.1%); 6 (5.3%) were treatment-related. One dose-limiting toxicity (bladder perforation in a urothelial pt with a neobladder) possibly related to study drug was observed with mono. MTD was not reached. No treatment-related deaths were observed. MK-4166 PK/PD showed target-mediated drug disposition concomitant with decreased GITR availability on T cells in blood with increasing doses. Four objective responses (4/45; ORR, 9%) were seen with combo in dose escalation. For ICI-naive melanoma pts (n = 13) in expansion, ORR was 69% (95% CI, 38-91), including 4 CRs and 5 PRs. No response was observed in 7 pts previously treated with ICI. High ORRs were observed in noninflamed and inflamed ICI-naive melanoma pts. Conclusions: MK-4166 at a dose up to 900 mg as monotherapy and in combination with pembro was well tolerated, with dose-related evidence of target engagement. Responses were observed with MK-4166 900 mg plus pembro, particularly in pts with melanoma naive to ICIs. Clinical trial information: NCT02132754.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 2521-2521 ◽  
Author(s):  
Ben Tran ◽  
Richard D. Carvajal ◽  
Aurelien Marabelle ◽  
Sandip P. Patel ◽  
Patricia LoRusso ◽  
...  

2521 Background: AMG 228 is an agonistic human IgG1 monoclonal antibody that binds to GITR (CD357), a TNFSFR costimulatory molecule expressed by effector/regulatory T cells. Dose escalation of this open label, first in human, phase 1 study evaluated the safety, pharmacokinetics (PK), pharmacodynamics, and maximum tolerated dose (MTD) and recommended phase 2 dose of AMG 228 in pts with advanced solid tumors. Methods: Pts with refractory advanced colorectal cancer (n = 13), squamous cell carcinoma of head and neck (n = 10), non–small cell lung cancer (n = 2), urothelial transitional cell carcinoma (n = 4), and melanoma (n = 1) received AMG 228 IV Q3W. Dose escalation was in two stages: single-pt cohorts until AMG 228-related grade > 2 adverse events (AEs), efficacy, or 90 mg dose reached (4 cohorts: 3, 9, 30, and 90 mg), followed by rolling six design (n = 2 to 6) until MTD or highest planned dose of 1200 mg reached (5 cohorts: 180, 360, 600, 900, and 1200 mg). Primary endpoints included incidence of dose-limiting toxicities (DLTs) and AEs and PK. Additional endpoints were objective response (RECIST 1.1) and evidence of biological activity. Results: In total, 30 pts (median age 63 y) were treated (3, 9, 30, and 90 mg, n = 1; 180 mg, n = 6; 360 mg, n = 4; 600 mg, n = 6; 900 mg, n = 4; 1200 mg, n = 6). Twenty-seven (90%) pts had treatment-emergent AEs; the most common were hypophosphatemia (23%), fatigue (23%), anemia (23%), nausea (20%), and pyrexia (20%). No DLTs occurred; the MTD was not reached. AMG 228 exposure was dose-related, with PK profiles at low doses (3 to 90 mg) consistent with target mediated drug disposition; doses > 360 mg achieved serum levels needed for 95% receptor occupancy on activated PBMCs. No evidence of T cell activation was observed despite complete target coverage in both tumor and peripheral blood. Among 29 evaluable pts, none had an objective response. Conclusions: In this population of pts with advanced solid tumors, AMG 228 Q3W was tolerable up to the highest tested dose (1200 mg), showing favorable PK. However, no clinical or immunological activity was observed in this limited number of pts. Clinical trial information: NCT02437916.


Author(s):  
Noboru Yamamoto ◽  
Toshio Shimizu ◽  
Kan Yonemori ◽  
Shigehisa Kitano ◽  
Shunsuke Kondo ◽  
...  

SummaryBackground This open-label, phase 1 study investigated TAS4464, a potent NEDD8-activating enzyme inhibitor, in patients with advanced/metastatic solid tumors (JapicCTI-173,488; registered 13/01/2017). The primary objective was dose-limiting toxicities (DLTs). Maximum-tolerated dose (MTD) was investigated using an accelerated titration design. Methods The starting 10-mg/m2 dose was followed by an initial accelerated stage (weekly dosing; n = 11). Based on liver function test (LFT) results, a 14-day, 20-mg/m2 dose lead-in period was implemented (weekly dosing with lead-in; n = 6). Results Abnormal LFT changes and gastrointestinal effects were the most common treatment-related adverse events (AEs). DLTs with 56-mg/m2 weekly dosing occurred in 1/5 patients; five patients had grade ≥ 2 abnormal LFT changes at 40- and 56-mg/m2 weekly doses. Further dose escalation ceased because of the possibility of severe abnormal LFT changes occurring. DLTs with weekly dosing with lead-in occurred in 1/5 patients at a 56-mg/m2 dose; MTD could not be determined because discontinuation criteria for additional enrollment at that particular dose level were met. As no further enrollment at lower doses occurred, dose escalation assessment was discontinued. Serious treatment-related AEs, AEs leading to treatment discontinuation, and DLTs were all related to abnormal LFT changes, suggesting that TAS4464 administration could affect liver function. This effect was dose-dependent but considered reversible. Complete or partial responses to TAS4464 were not observed; one patient achieved prolonged stable disease. Conclusions MTD could not be determined due to TAS4464 effects on liver function. Further evaluation of the mechanism of NEDD8-activating enzyme inhibitor-induced abnormal liver function is required. Trial registration number JapicCTI-173,488 (registered with Japan Pharmaceutical Information Center). Registration date 13 January 2017


2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A315-A315
Author(s):  
Bhumsuk Keam ◽  
Tae Min Kim ◽  
Do-Youn Oh ◽  
Chan-Young Ock ◽  
Won Ki Kang ◽  
...  

BackgroundIMC-001 is a fully human IgG1 monoclonal antibody that binds to human PD-L1 and mediate the antibody-dependent cell-mediated cytotoxicity. The main objectives of this study were to evaluate the safety, pharmacokinetics, and pharmacodynamics of IMC-001 in patients with advanced solid tumors. Here, we report final result of the phase 1 study of IMC-001.MethodsThis open-labeled phase 1 study used standard 3+3 dose-escalation design, dose ranging from 2 to 20 mg. IMC-001 was administered intravenously every two weeks until disease progression or unacceptable toxicity. Dose limiting toxicity (DLT) window was defined as 21 days from the first dose. Adverse events (AEs) were assessed using CTCAE v4.03, and tumor response was assessed by and the Response Evaluation Criteria In Solid Tumors (RECIST) version v1.1.ResultsFifteen subjects (8 Male, 7 Female; Median age : 58 [range 39–69]) were included in 5 dose escalation cohorts. No DLT was observed and the maximum tolerated dose was not reached. Most common AEs were general weakness, decreased appetite, fever, and cough. No Grade 4 or 5 treatment emergent AEs (TEAEs) were reported during the study and no TEAE or serious AE led to treatment discontinuation or death. There were no infusion-related reactions during this study. Grade 2 immune-induced thyroiditis and diabetes mellitus suspected to be related to IMC-001 were seen in one subject at 2 mg/kg cohort. Over the dose range of 2 to 20 mg/kg IMC-001, AUC 0-14d, AUC 0—∞, and Cmax generally appeared to increase in a dose proportional manner for each step of dose escalation. Of the 15 enrolled patients, one subject with colon cancer showed partial response, and disease control rate was 33.3%. There were total 3 biliary tract cancer patients (1 GB cancer, 2 Cholangiocarcinoma) who received ≥3 lines of systemic therapies prior to this trial. They all had stable disease during IMC-001 treatment, and one cholangiocarcinoma subject received the treatment for 434 days.ConclusionsIMC-001 demonstrated a favorable safety profile up to 20 mg/kg given IV every 2 weeks and showed encouraging preliminary efficacy in patients with advanced solid tumors. Based on PK and PD data, 20 mg/kg was selected as recommended Phase 2 dose (RP2D).Ethics ApprovalThis study was approved by Institutional Review Board; approval number SMC 2018-01-007-001 and H-1801-042-913.


Author(s):  
Crystal S. Denlinger ◽  
Vicki L. Keedy ◽  
Victor Moyo ◽  
Gavin MacBeath ◽  
Geoffrey I. Shapiro

SummaryBackground Overactivation of human epidermal growth factor receptor 3 (HER3) triggers multiple intracellular pathways resulting in tumor cell survival. This Phase 1 study assessed the safety, efficacy, and pharmacokinetics (PK) of seribantumab, a fully human anti-HER3 monoclonal antibody. Methods Adult patients with advanced or refractory solid tumors were treated in six dose cohorts of seribantumab: 3.2, 6, 10, 15, or 20 mg/kg weekly, or 40 mg/kg loading dose followed by 20 mg/kg weekly maintenance dose (40/20 mg/kg) using a modified 3 + 3 dose escalation strategy with cohort expansion. Primary objectives were identification of a recommended Phase 2 dose (RP2D) and determination of objective response rate. Secondary objectives were assessment of safety, dose-limiting toxicities, and PK. Results Forty-four patients (26 dose escalation; 18 dose expansion) were enrolled. Seribantumab monotherapy was well tolerated with most adverse events being transient and mild to moderate (grade 1 or 2) in severity; maximum tolerated dose was not reached. The highest dose, 40/20 mg/kg, was identified as RP2D. Best response was stable disease, reported in 24% and 39% of patients during the dose escalation and expansion portions of the study, respectively. Seribantumab terminal half-life was ≈100 h; steady state concentrations were reached after 3–4 weekly doses. Conclusions Seribantumab monotherapy was well tolerated across all dose levels. Safety and PK data from this study support further seribantumab investigations in genomically defined populations.Clinical trial registration NCT00734305. August 12, 2008.


2021 ◽  
Author(s):  
Crystal Denliger ◽  
Vicki L Keedy ◽  
Victor Moyo ◽  
Gavin MacBeath ◽  
Geoffrey I Shapiro

Abstract BACKGROUND: Overactivation of human epidermal growth factor receptor 3 (HER3) triggers multiple intracellular pathways resulting in tumor cell survival. This Phase 1 study assessed the safety, efficacy, and pharmacokinetics (PK) of seribantumab, a fully human anti-HER3 monoclonal antibody.METHODS: Adult patients with advanced or refractory solid tumors were treated in six dose cohorts of seribantumab: 3.2, 6, 10, 15, or 20 mg/kg weekly, or 40 mg/kg loading dose followed by 20 mg/kg weekly maintenance dose (40/20 mg/kg) using a modified 3+3 dose escalation strategy with cohort expansion. Primary objectives were identification of a recommended Phase 2 dose (RP2D) and determination of objective response rate. Secondary objectives were assessment of safety, dose-limiting toxicities, and PK.RESULTS: Forty-four patients (26 dose escalation; 18 dose expansion) were enrolled. Seribantumab monotherapy was well tolerated with most adverse events being transient and mild to moderate (grade 1 or 2) in severity; maximum tolerated dose was not reached. The highest dose, 40/20 mg/kg, was identified as RP2D. Best response was stable disease, achieved by 24% and 39% of patients during the dose escalation and expansion portions of the study, respectively. Seribantumab terminal half-life was ≈100 hours; steady state concentrations were reached after 3–4 weekly doses. CONCLUSIONS: Seribantumab monotherapy was well tolerated across all dose levels. Safety and PK data from this study support further seribantumab investigations in genomically defined populations. CLINICAL TRIAL REGISTRATION: NCT00734305.DATE OF REGISTRATION: August 12, 2008.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 2007-2007
Author(s):  
Michael Rosenzweig ◽  
Joycelynne Palmer ◽  
Ni-Chun Tsai ◽  
Ralf Buettner ◽  
Lupe Duarte ◽  
...  

Abstract Introduction: Despite significant progress in the treatment of multiple myeloma (MM), the disease remains incurable and typically follows a pattern of multiple responses and relapses. In the relapsed/refractory MM setting (RRMM), outcomes for patients may be particularly discouraging. New treatments that are safe and effective are therefore of urgent need for this population. Since its FDA approval in 1998 for the treatment of rheumatoid arthritis, leflunomide has been used in over 300,000 patients worldwide. Leflunomide is hepatically cleared and has a favorable toxicity profile even when given over long periods. Its primary mechanism of action is inhibition of pyrimidine synthesis by targeting dihydroorotate dehydrogenase, thus achieving anti-proliferative effects on B and T lymphocytes. The anti-neoplastic potential of this agent has been studied in a number of pre-clinical tumor models. Leflunomide's immunoregulatory action may be related to functional inhibition of CD4+ effector T cells, including Th17 cells as well as dysregulation of T regulatory cells (Tregs). We found that leflunomide-treated C57BL/KaLwRij mice engrafted with 5TGM1 cells had more robust expansion of CD8+ cytotoxic T cells and subsequent decrease of CD4+ Tregs compared to untreated mice. We have also noted that leflunomide impairs growth of MM cells at least partly through inhibition of PIM kinases and c-Myc signaling. We present here final results from a phase 1 study of leflunomide in patients with RRMM. Methods: This single center, single agent, phase 1 dose-escalation trial was designed to determine the maximum tolerated dose of leflunomide in patients with RRMM. The trial implemented a modified rolling six phase 1 dose escalation design. The primary objectives were as follows: 1) to determine the maximum tolerated dose and recommended phase 2 dose of leflunomide; 2) to assess the safety and tolerably of leflunomide at each dose level by evaluation of toxicities. Leflunomide was administered at a loading dose of 100 mg daily for the first three days, then daily in 28-day cycles. The starting dose of daily leflunomide was 20 mg daily, with dose escalation in increments of 20 mg/day, up to 60 mg/day. Dose de-escalation in decrements of 10mg/day was planned. Results: A total of 12 patients have been enrolled starting in December 2015 and treated. The median age is 68 (range 48 - 85), and the median number of prior therapies is 5 (range: 3 - 14). Nine patients had prior autologous stem cell transplant. Double refractory (lenalidomide/bortezomib) disease was noted in 9 patients. High-risk cytogenetics were observed in 5 patients including 2 patients with del17p. All 12 subjects were evaluable for toxicity. One subject was not evaluable for response because of non-compliance. Of the eleven patients evaluable for response, the median number of cycles was 3 (range 1- 15). The median follow up was 177 days (range: 42 - 602). Three patients were treated on DL 1 (20 mg) and three on DL3 (40 mg) without incidence of DLT. At DL5 (60 mg), one patient had a DLT with grade III elevation of alanine aminotransferase; an additional three patients were enrolled at this dose level without further DLTs. One out of 12 subjects remains on treatment, 8 patients were removed from study due to disease progression, two due to adverse events (bacteremia at 60 mg, possibly related to study drug and angioedema at 40 mg, not related to study drug) and one from noncompliance. The most common toxicities were hematologic. There were 4 patients with grade 1 or 2 neutropenia on the 20 and 40 mg dose levels and 1 patient with grade 4 lymphopenia on the 40 mg dose. Except for the DLT, all non-hematologic toxicities were ≤ grade 2. Response: Although not all patients were treated at the 60 mg dose, a clinical benefit rate of 90% has been seen, with 9/10 achieving stable disease (SD). The median duration of SD among 9 patients thus far is 56 days (range: 27-401). In the five evaluable patients with high risk cytogenetics, four of them achieved a clinical benefit. Two subjects had SD lasting nearly one year or longer. In this small cohort, no association between dose and benefit was observed. Conclusion: Leflunomide is a safe and well-tolerated oral option for patients with RRMM, with a clinical benefit from single agent dosing. On the basis of our preclinical work showing synergistic inhibition of MM using leflunomide, pomalidomide, and dexamethasone, we plan clinical testing of this drug combination. Disclosures Rosenzweig: Celgene: Speakers Bureau. Krishnan:Janssen: Consultancy, Speakers Bureau; Sutro: Speakers Bureau; Onyx: Speakers Bureau; Takeda: Speakers Bureau; Celgene: Consultancy, Equity Ownership, Speakers Bureau. Forman:Mustang Therapeutics: Other: Licensing Agreement, Patents & Royalties, Research Funding.


2020 ◽  
Vol 38 (15_suppl) ◽  
pp. TPS3157-TPS3157
Author(s):  
Steven O'Day ◽  
Chethan Ramamurthy ◽  
Andrea J. Bullock ◽  
Anthony B. El-Khoueiry ◽  
Lernik Ohanjanian ◽  
...  

TPS3157 Background: AGEN1181 is a novel Fc-optimized anti-CTLA4 antibody, currently being evaluated in an ongoing multi-center, open-label, phase 1 study in all advanced solid tumors as mono-therapy and combination with anti-PD-1 antibody, AGEN2034 (NCT03860272). AGEN1181 is Fc-engineered to harness a novel mechanism for enhanced FcγR-dependent functionality relative to first-generation CTLA-4 antibodies. In pre-clinical models, AGEN1181 enhances T cell priming, depletion of intratumoral regulatory T cells (Treg) and improved memory formation compared to first-generation anti-CTLA-4 antibodies. Most notably, AGEN1181 demonstrates improved binding to FcyRIIIA and superior T cell responsiveness in populations that only express the low affinity FcγRIIIA receptor relative to first-generation IgG1 CTLA-4 antibodies. The combination of AGEN1181 and AGEN2034 further enhances T cell activation and effector function. Methods: This phase 1 study is an open-label, multi-center dose-escalation designed to evaluate the safety, tolerability, dose limiting toxicity (DLT) PK, and pharmacodynamic profiles of patients with refractory advanced solid tumors who did not receive an anti-CTLA4 previously. The study is being conducted in 3 arms; with patients assigned using a standard 3+3 dose escalation design in the mono-therapy arms with AGEN1181 and an accelerated design in the combination with AGEN2034 arm. AGEN1181 is administered as IV infusion as mono-therapy on Day 1 of every 3 weeks (0.1,0.3,1,2,4 mg/kg), every 6-weeks (1,2,4 mg/kg) in parallel cohorts and every 6-weeks (0.1,0.3,1,2,4 mg/kg) in combination with AGEN2034 (3mg/kg Q2Weeks) until disease progression or unacceptable toxicity (maximum 2 years). All 3 Arms are open and enrolling patients. The study is expected to enroll approximately 80 evaluable patients with solid tumors. Dose reductions are not allowed in the event of AGEN1181-related toxicities. Currently 3 cohorts have been completed, first cohort in the combination arm and the fourth cohort in the monotherapy arm are enrolling. Preclinical and clinical assessment of AGEN1181 supports continued development as a potential therapy for refractory or relapsed advanced solid tumors. Clinical trial information: NCT03860272 .


2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 3005-3005 ◽  
Author(s):  
Kyriakos P. Papadopoulos ◽  
Frank Yung-Chin Tsai ◽  
Todd Michael Bauer ◽  
Lucas Muigai ◽  
Yu Liang ◽  
...  

3005 Background: Arginase is secreted by myeloid-derived suppressor cells (MDSCs) and polymorphonuclear cells (PMNs) in the tumor microenvironment, depleting arginine, an amino acid required for T-cell activation and proliferation. CB-1158 is an oral small molecule inhibitor of arginase. CB-1158 reverses PMN- and MDSC-mediated suppression of T-cells in ex vivo human models, and increases plasma and tumor arginine levels in mouse syngeneic tumor models leading to increased pro-inflammatory markers and activated CD8 T-cells in the tumor. CB-1158 has single agent efficacy in mouse tumor models and synergistically enhances the antitumor efficacy of checkpoint inhibitors. Methods: This is an ongoing phase 1 study to evaluate safety and tolerability of CB-1158 as a monotherapy and in combination with anti-PD-1 in pts with solid tumors. Pharmacokinetics (PK), anti-tumor effects, and biomarkers, including plasma arginine, arginase activity, and effects on immune function in blood and in tumors will be evaluated. CB-1158 was administered BID orally in 28-day cycles. Escalating doses were administered to cohorts for safety evaluation. Additional pts were enrolled at dose levels determined to be safe to support biomarker objectives. Results: Nine pts have been enrolled across two monotherapy dose escalation cohorts (50 and 100 mg) and biomarker cohorts. CB-1158 was rapidly absorbed (Tmax = 4 h) and was cleared with a half-life of 6 h. At doses of 50 and 100 mg, steady-state plasma trough levels were 1.6 and 4.5 µM, sufficient to achieve > 90% arginase inhibition, and plasma arginine levels increased 2.4- and 4-fold, respectively. CB-1158 has been well tolerated with no DLTs or drug-related Grade 3 AEs. Dose escalation is ongoing and updated safety, PK and biomarker data will be presented. Conclusions: CB-1158 is a first-in-class inhibitor of the myeloid-derived immunosuppressive enzyme arginase. CB-1158 has been well tolerated and achieves on-target inhibition resulting in increases in plasma arginine, an amino acid required for T-cell immune responses. Clinical trial information: NCT02903914.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A553-A553
Author(s):  
Elaine Shum ◽  
Matthew Reilley ◽  
Yana Najjar ◽  
Adil Daud ◽  
John Thompson ◽  
...  

BackgroundXmAb20717 is a humanized bispecific monoclonal antibody that simultaneously targets PD-1 and CTLA-4. We report updated data on patients treated at the recommended expansion dose from an ongoing, multicenter, Phase 1, dose-escalation and -expansion study of intravenous XmAb20717 in patients with selected advanced solid tumors that progressed after treatment with all standard therapies or with no standard therapeutic options.MethodsA maximum tolerated dose was not reached in dose escalation. XmAb20717 10 mg/kg every 2 weeks (Q2W) was selected as the expansion dose, based on consistent T-cell proliferation in peripheral blood indicative of dual PD-1/CTLA-4 checkpoint blockade, and response to treatment (RECIST[1.1]).1 Parallel expansion cohorts included ~20 patients each with melanoma, renal cell carcinoma (RCC), non-small cell lung cancer (NSCLC), castration-resistant prostate cancer (CRPC), and a basket of tumor types without an FDA-approved checkpoint inhibitor (CI). Patients treated with 10 mg/kg in dose escalation were pooled with expansion cohorts for analysis of clinical activity and safety.ResultsAs of 9 June 2021, 110 patients, ranging in age from 39 to 89 years and 66.4% male, were treated, and 5 were continuing treatment. Patients had received a median of 4 prior systemic treatment regimens, including CI therapy for 64.5%. The objective response rate was 13.0% (10/77 patients evaluable for efficacy), including 1 complete response (melanoma [confirmed]) and 9 partial responses (confirmed: 1 melanoma, 2 RCC, 2 CRPC, 1 ovarian cancer; unconfirmed: 1 melanoma, 2 NSCLC). The CRPC responders (2/7 with RECIST-measurable disease) had confirmed PSA decreases ≥ 50% from baseline (to 0.02 and 0.3 ng/mL); neither had progression on bone scans. All responders had prior CI exposure, except those with CRPC. Robust CD4 and CD8 T-cell activation was seen. Low baseline tumoral expression of myeloid recruitment genes, including IL-8, was associated with clinical benefit. Grade ≥ 3 immunotherapy-related adverse events in ≥ 3 patients included rash (16.4%), transaminase elevations (9.1%), hyperglycemia (4.5%), acute kidney injury (3.6%), amylase and lipase increased (2.7%), and lipase increased (2.7%).ConclusionsPreliminary data indicate 10 mg/kg XmAb20717 Q2W was associated with complete and partial responses in multiple tumor types and was generally well-tolerated in these heavily pretreated patients with advanced cancer. Changes in T-cell populations in the periphery and tumor are consistent with robust dual checkpoint blockade. These findings support further development of XmAb20717 in advanced solid tumors, including metastatic prostate cancer.Trial RegistrationNCT03517488ReferencesShum E, Daud A, Reilley M, et al. Preliminary safety, pharmacokinetics/pharmacodynamics, and antitumor activity of XmAb20717, a PD-1 x CTLA-4 bispecific antibody, in patients with advanced solid tumors. JITC 2020;8(3):A247-8.Ethics ApprovalThe study was approved by each institution’s IRB.


2021 ◽  
Vol 39 (15_suppl) ◽  
pp. TPS3161-TPS3161
Author(s):  
Ecaterina Elena Dumbrava ◽  
Amit Mahipal ◽  
Xin Gao ◽  
Geoffrey Shapiro ◽  
Jason S. Starr ◽  
...  

TPS3161 Background: The p53 pathway has been implicated in antitumor immunity, including antigen presentation and T-cell proliferation. Loss of p53 function can increase resistance to immunotherapy across many tumor types. Eprenetapopt (eprenet) is a small molecule that stabilizes the folded structure of p53, resulting in activation of mutant p53 and stabilization of wild-type (WT) p53. It also targets the cellular redox homeostasis, resulting in induction of apoptosis in tumor cells. In vivo, mice carrying supernumerary copies of the TP53 gene harbor a pro-inflammatory tumor microenvironment, an effect recapitulated in TP53 normal-copy mice treated with eprenetapopt. Combining eprenetapopt and anti-PD1 or anti-CTLA4 therapy resulted in enhanced tumor growth inhibition and improved survival in TP53 WT mice inoculated with B16 melanoma and MC38 colon adenocarcinoma cells . Based on these results, we hypothesized that eprenet-induced p53 stabilization may augment response to immunotherapy. To test this hypothesis, we are conducting a phase 1b/2 study of eprenet in combination with pembrolizumab (eprenet+pembro) in pts with solid tumors. Methods: The primary objectives are to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) and to assess the safety and tolerability of eprenet+pembro in pts with advanced solid tumors. The secondary objectives are to estimate the anti-tumor activity and to describe the pharmacokinetics of the combination. Exploratory objectives include assessing predictive and pharmacodynamic markers of response. The study includes a safety lead-in with a 3+3 dose de-escalation design for pts with advanced solid tumors with known tumor TP53 mutation status ( TP53 WT is acceptable) (max 18 pts), followed by expansion cohorts in pts with NSCLC, gastric/GEJ and urothelial cancer (max 100 pts). In expansion, pts with urothelial and gastric cancers must be naïve to anti-PD-1/ L1 therapy. Eprenet is given IV once daily on Days 1–4 while pembro is administered on Day 3 of each 21-day cycle. The RP2D of eprenet+pembro is considered the dose at which ≤ 1 of 6 pts in a cohort has a dose-limiting toxicity (DLT). Primary endpoints are occurrence of DLTs, adverse events (AEs) and serious AEs with eprenet+pembro. Key secondary endpoints are best objective response, progression free survival and overall survival. Exploratory endpoints include gene mutations by next generation sequencing (including TP53), mRNA expression, multiplex immunohistochemistry and transcriptomics, multiplex flow cytometry on peripheral blood mononuclear cells and cytokines in serum. Continuous monitoring of toxicity will be conducted. The trial opened in May 2020 and is actively enrolling patients. Clinical trial information: NCT04383938.


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